Detection ofOrientia tsutsugamushi, the Causative Agent of Scrub Typhus, in a Novel Mite Species,Eushoengastia koreaensis, in Korea

Abstract

To identify potential vector species of scrub typhus in the Republic of Korea (ROK), chigger mites were harvested from wild rodents captured at nine localities in October 2005. The bodies of the chigger mites were individually punctured with a fine pin, squeezed out internal contents, and examined for Orientia tsutsugamushi DNA by nested polymerase chain reaction. The exoskeleton of associated chiggers was mounted on glass slides with polyvinylalcohol (PVA) medium for identification. Among 830 individuals belonging to 4 genera and 14 species, O. tsutsugamushi was detected from 22 chiggers of six species, with an overall infection rate of 2.7%. The infection rate was highest for Leptotrombidium palpale (5.3%), followed by Neotrombicula japonica (4.3%), Leptotrombidium scutellare (3.7%), Leptotrombidium orientale (3.6%), Eushoengastia koreaensis (1.9%), and Leptotrombidium pallidum (1.5%). This study first reported O. tsutsugamushi infection from N. japonica and E. koreaensis larvae in the ROK. The population densities of L. pallidum (33.4 chiggers/rodent), historically confirmed as a primary vector of scrub typhus in the ROK, were high, whereas its infection rate was relatively low (1.5%). However, E. koreaensis was only collected from 154 individuals at seven collection sites and its infection rate was demonstrated relatively high (mean 1.9%). Additional studies are needed to determine the role of vector species in the epidemiology of scrub typhus.

Syndromic classification of rickettsioses: an approach for clinical practice

“…87 Other genera of the Trombiculidae family, such as Neotrombicula (N. japonica) and Eushoengastia (E. koreaensis), have also been implicated as possible vectors. 88 The clinical manifestations may vary from mild to severe. Heart failure, acute renal failure, and central nervous system and respiratory system compromise, with interstitial pneumonia and acute respiratory distress syndrome (ARDS) are the most frequent causes of complications and death.…”

Rapid Increase in Scrub Typhus Incidence in Mainland China, 2006–2014

“…3,4 The clinical manifestations of scrub typhus can range from unapparent or atypical febrile illness to life-threatening symptoms including acute hearing loss and multiple organ failure. 5,6 It is estimated that there are currently more than 1 billion people living in scrub typhus endemic areas, and the incidence has begun to increase over the last decade.…”

Effect of Latitude and Seasonal Variation on Scrub Typhus, South Korea, 2001–2013

“…1 Scrub typhus occurs throughout the Asia-Pacific region and represents a significant public health issue in Asia, 2 where 1 billion people are at risk for this disease. 3 Moreover, an increasing incidence of scrub typhus has been reported in some Asian countries. 4 The incidence of scrub typhus may be related to temperature, rainfall, and socioeconomic factors.…”